Rotary Connector System for Piano Fallboard Alignment
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Solution Overview
Problem
The existing rotary dampers for keyboard musical instruments face challenges in accurately fitting the fallboard to the key slip, leading to assembly errors and increased production costs due to the need for multiple socket sizes and labor-intensive adjustments.
Innovation Solution
A rotary connector system with a stationary and rotatable portion, and a position adjuster that allows for precise alignment on a virtual plane defined by the up-and-down and fore-and-aft directions, enabling the fallboard to be properly positioned without requiring new components, thus reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prior art rotary dampers are used with fixed-size sockets, then the structure is simple, but assembly precision deteriorates due to machining and assembling errors causing offset between fallboard and key slip
Solution Approach 1:
The rotary connector system incorporates adjustable sockets that can be dynamically positioned along guide rails in both horizontal and vertical directions, allowing real-time compensation for assembly errors and achieving precise alignment between the fallboard and key slip without requiring complex custom components
Solution Approach 2:
The socket positions are made variable through adjustment mechanisms that allow changing the location of sockets along guide rails, transforming fixed-parameter assembly into variable-parameter assembly to accommodate machining tolerances and achieve optimal alignment
2Manufacturing precision
If multiple sockets of different sizes are prepared to compensate for assembly errors, then alignment precision improves, but production cost increases and assembly time increases
Solution Approach 1:
A single type of socket is designed with multi-functionality, serving both as a mounting component and as an adjustable positioning element. The universal socket design eliminates the need for multiple specialized components while maintaining the ability to compensate for assembly errors through position adjustment along guide rails
Solution Approach 2:
Guide rails are pre-installed on the fallboard and cabinet at predetermined positions, providing a ready-made adjustment framework before assembly begins. This preliminary preparation enables workers to quickly adjust socket positions without needing to measure or calculate, significantly improving assembly efficiency
3Stability of the object's composition
If cylinders are embedded in boss portion and shafts are secured to cabinet, then the connection is stable, but assembly difficulty increases due to tolerance requirements and adjustment complexity
Solution Approach 1:
Adjustable sockets act as intermediary components between the fixed cabinet structure and the movable fallboard, absorbing dimensional variations and assembly errors. These intermediaries provide a stable connection while simplifying the assembly process through easy adjustment along guide rails rather than requiring precise pre-positioning
Data Source
AI summary
A front fallboard, a rear fallboard and a hinge connected between them form in combination a fallboard assembly connected between side arms of a piano cabinet by means of a pair of rotary connectors, and each of the rotary connectors includes a front metal plate connected to the side surface of the front fallboard, a rear metal plate connected to the bottom surface of the side art defining a recess and a rotary damper; since the recess is wider than the rear metal plate already combined with the rotary damper, the rear metal plate is movable on a virtual plane defined by a fore-and-aft direction and an up-and-down direction; while a worker is seeking the optimum positions of the rotary connectors, self-tapping screws keep the rear metal plates in the recesses so that the worker drives woodscrews into the side arms through main holes or auxiliary holes.